Process for devulcanizing india-rubber.



-on'rirnn STATES PATENT OFFICE.

MORI'IZ KijRNER, or GRI'TNAU, GERMANY.

PROCESS FOR; DEVULCANIZING INDIA-RUBBER.

No Drawing.

To all whom it may concernf Be it known that T,Mon1rz Konnnn, chemist, asubject of the German Emperor, residing-at Griinau, Germany. haveinvented 5 a certain new and useful Process for Devul- Specification ofLetters Patent.

Application filed November 2. 1905. Serial No. 285.637.

Patented Mar. 29, 19,10.

canizing India-Rubber, of which the folj lowing is a specificati on. Y

The ,problemof completely removing the sulfur tron vulcanizedindla-rubber. with- .out in any way 1n ur1ously allccting its quahty.has hitherto not been solved in a completely satisfactory manner.

The present invention has for its object toattain this result ascompletely as posslhle. v v

' Theprocess consists in heating the vul- "T'ianiz'ed india-rubber withmedia such as toluene,- xylene or benzin, which dissolve inclia rubberunder pressure, at a high tomie'rature and causing water or steam to actupon the solution obtained for a considin comparison with that. obtainedaccording: to the present process, as it dissolves less easily intheordiuary solvents and its solubility in the latter graduallydecreases.

112mm pins.

T. 100 kilograms of used bicycle tubes are heated with 5001a; 0t benzin(or toluene or xylene) to 130-150 ('1. for 10 hours in a closed vessel,after which the solution obtaiued is heated with 50 kg. of water to 130(1. in a closed receptacle to" 5 hours and then the rubber solutiondistilled to drive oil the solvent.

IT. 100 kilograms of.bicycle tubes are heated with 500 kg. of benzin (ortoluene erable time at a high ten'iperature, the heatin'gv of theindia-rubber with theindiarubber solvent being efl'ected in the presenceof water. or steam under pressure or the indie-rubber solutioir beingfirst relieved of loading. substances and other admixtures and thenheated with water or steam, prefrerably' under pressure.

After the aqueous 3O layer has been'scparated from the indiarubbersolution mechanically,-the solvent;

subsequent treatment of the indie-rubbersolution with water or steam inthe heat is omitted,a product results which is inferior If thevulcanized or xylene) and kg. of water for 10 hours in a closed vesselto 130-150 C. The solution obtained is then freed from the solvent in asuitable manner.

What I claim is 1. The improvement in the devulcanization of vulcanizedindia-rubber b treatment.

with india-rubber solvent at a high tempera-i ture and under prcssure,which consists in adding to the said treatment a treatment with waternot'containing alkaline substances for several hours at a temperatureabove (3., substantiallyXas described.

2. The herein described process for the dcvuleanization of vulcanizedindia-rubber by treatment with an india-rubber solvent at a hightemperature and under pressure, which consists in heating- 100 parts ofvulcanized india-rubber with 50 0 parts of benzin and 50, parts of waterin a closed receptacle to -l50 C. for about 10 hours and then separatingthe solvent from the solution thus obtained, substantially as described.i i In testimony whereof I have set my hand hereuntoin the presence oftwo subscribing witnesses. v v

t MORITZKURNERQ Witnesses:

CARL OEHLERT, Fnrrz THOMAS.

